In the trend that energy conservation and environmental protection are promoted, LED has been applied more and more widely due to its feature of energy conservation and environmental protection, long service life, fast start-up, good safety and stability. At present, lighting devices of other sources have been gradually replaced by LED lighting device.
LED products may break down during its usage due to the penetration of moisture or other harmful gases into the base plate or metal oxidation. When the products are used for outdoor lighting, the sealing and waterproof performance should be especially taken into consideration.
Traditional LED products, with the waterproof structure of box-packaged and screws-tightened, are usually heavy and thick, which have great influence to the heat dissipation performance. In the patent application 200910054820.8, a waterproof sealing structure and its preparation process of LED module are disclosed, and the waterproof sealing structure includes LED element, base plat, electrode, and circuit board. The LED module is comprehensively covered with a layer of thin film PARYLENE of which the thickness is 3˜25 MM. The film is even, tight, transparent, without any voids, and completely fit, to protect the LED module from intrusion of water, damp and air, and also facilitating heat dissipation of LED element. The thin film PARYLENE is one of the PARYLENE N, PARYLENE C, PARYLENE D or PARYLENE VT4.
In the above patent application, coverage of parylene thin film on the entire LED module is applied to realize sealing and waterproofing. The disadvantages of it include that the film can be easily scratched and damaged, rendering short service life. Meanwhile, complete coverage of thin film on the entire lamp means harder craft and higher cost.